386 Pierre A. Fish 



William Hunter did much to extend the practice of injection 

 by producing some very beautiful specimens and the impetus 

 thus given by these early anatomists has brought the method 

 down to us with but few if any radical changes. 



Admirable as these results were concerning the body as a 

 whole, it became apparent that they were quite inadequate 

 when a more thorough and accurate knowledge of brain mor- 

 phology was demanded, thus it came about that greater care 

 was used in the removal of the brain and special methods of 

 treatment were devised, and the importance of technique be- 

 came more and more emphasized, especially so within the last 

 two or three decades. 



The consistence of the brain coupled with the difficulty of 

 its removal renders it a difficult organ to preserve. History 

 gives good evidence that the advance in the knowledge of 

 brain structure has been largely dependent upon improved 

 methods of manipulation. 



The purpose of hardening is to bring the brain into a proper 

 condition for the continued study of either its fine or gross 

 anatomy, the former usually requiring some special care in 

 methods and after-treatment which may be dispensed with in 

 the latter without apparent detriment. 



For the study of the gross anatomy either wet or dry prepar- 

 ations may be available. The preference generally being 

 given to the wet since they are more easil}' and quickly pre- 

 pared and because they admit of further and careful dissection 

 at any time after once being well hardened. A shrinkage in 

 the tissues must necessarily occur during this process but it is 

 not usually carried so far as in the case of the dry prepar- 

 ations. Nor is there such an unnatural color unless some 

 colored preservative is employed. But there is the disad- 

 vantage of a possible ruination of the specimens by over-ex- 

 posure to the air, evaporation or deterioration of the preserva- 

 tive and a consequent expense in renewing the same. 



For the study of surface anatomy and of certain parts dis- 

 sected out before the specimen is "dried," there is no reason 

 why, if successfully prepared, the dry method would not 

 answer most needs and have the further advantage of re- 

 maining permanent in the air. 



